Low back pain in the older adult may be a consequence of relative strength deficits in the lumbar musculature. Obesity may exacerbate strength deficits. Pain-related fear and avoidance is a psychosocial factor that is strongly related to chronic disability. However, the relationships between pain-related fear, physical function and chronic low back pain in the obese, older adult are not known. The national obesity crisis continues, concurrent with the increased prevalence of low back pain and physical disability. The lack of understanding of the factors leading to back pain related disability in this population is therefore a serious scientific deficit. We have shown that resistance exercise can ameliorate lumbar strength deficits in older adults, and can improve psychological well being. It is unclear however, if lumbar exercise alone or total body resistance exercise optimizes lumbar strength and functional improvement, and reduces fear avoidance beliefs and in the obese, older adult. This proposed project will be the first to address these deficits in the literature by comparing the effects of two different resistance exercise protocols on pain back pain symptoms, fear avoidance beliefs, and physical function in older obese adults. This proposed study is a prospective, randomized, controlled study to determine whether one of two resistance exercise protocols reduces fear avoidance beliefs, increases mobility, and reduces pain in obese individuals (N=60;60-85 years) with low back pain symptoms. This is a repeated- measures, three group design in which the effects 4 months of resistance exercise (either total resistance exercise or isolated lumbar exercise) will be compared standard care. The main outcome measure will be subjective lumbar pain ratings (visual analogue scale 0-10). Other critical measures will include pain-related fear and avoidance belief assessments (Tampa Scale of Kinesiophobia, Fear Avoidance Beliefs Questionnaire, Pain Catastrophizing Scale), functional mobility (chair rise time, stair climb ability), ambulation (graded walking tests, community ambulation), and self-reported disability related to lumbar pain symptoms (Oswestry Survey). Measurements will be collected before the 4 month intervention period at baseline, and after the intervention period. Specific measures will be captured at increments during the training period at months 1, 2 and 3. A series of analyses of covariance will be used to determine whether either of the resistance exercise interventions improves the main outcome measure or other critical measures. Hierarchal regression models will be generated to determine which outcome variable changes contribute most to the variance of models for functional mobility and ambulation. This study will provide critical data necessary to establish the relationships between psychological and functional factors relating to disability, and options for optimizing interventions to reduce lumbar pain related disability in the older obese segment of the population. PUBLIC HEALTH RELEVANCE: Obesity induces lumbar muscle strength deficits and elevates pain-related fear avoidance beliefs, both of which contribute to disability due to chronic low back pain. A strategy to combat both the strength deficits and psychosocial aspects of low back pain is needed to prevent back pain related disability and a future of functional dependence. This research will examine whether resistance exercise programs (one that isolates low back muscles alone, or total body resistance exercise) can increase lumbar muscle strength and functional mobility, and reduce fear avoidance beliefs in the obese older adult.